Provide for pathology support services in rodent bioassays. This will include tissue processing for light and electon, microscpy tissue preparation and staining, and histopathologic and electron microscopic diagnoses. This project will have work done for the Tumor Pathology Section pertaining to the organization and conducting seminars, workshops, etc., and will serve as consultants where necessary as technical and professional supportive service to bioassay contractors and subcontractors. This project will also provide a histology laboratory having capabilities of processing routine and special staining of rodent tissues and will be capable of processing and making histologic diagnoses up to 70,000 tissues per year multiply embedded.